Automatically controlled heating system



Aug. 20, 1935. E. L. MAYO 2,012,067

AUTOMATICALLY CONTROLLED HEATING SYSTEM I I Filed June 9, 1932 3 Sheets-Sheet 1 INVENTOR.

Edward Levy Mayo.

' Q MK ATTOTQNEY. I

Aug. 20, 1-935. E. MAYO 2,012,067

AUTOMATICALLY CONTROLLED HEATING SYSTEM Filed June 9, 1952 5 Sheets-Sheet 2 V INVENTOR. Edward Lev Mayo. BY

Aug. 20,- 1935. E. MAYO AUTOMATICALLY CONTROLLED HEATING SYSTEM Fild June 9, 1952 3 Sheets-Sheet 3 INVENTOR. Edward Lev Mayo.

ATT

, summer hot water is wanted only at the faucet;

I Patented Aug. 20, 1935 PATENT OFFICE AUTOMATICALLY CONTROLLED HEATING SYSTEM Edward Levy Mayo, Cleveland, Ohio, assignor to The Bishop,& Babcock Mfg. Company, Cleveland, Ohio, acorporation of Ohio Application June 9, 1932, Serial No. 616,275;

'32 Claims.

My invention has particular advantages when applied to heating systems in which steam or circulating hot water is employed as a heating medium and in which heat is supplied to the water or steam by an automaticelectrically controlled fuel burning apparatus. I

In connection with hot water or steam heating systems, it is desirable to provide a constant supply of hot water for use at faucets, such as faucets in bathrooms, lavatories, etc., and to maintain the same at a desirable temperature above a predetermined minimum temperature, irrespective of the heat demands upon the system for heating the rooms of the building.

Thus, for example, in winter hot water is wanted at the faucets and heat is also wanted in the rooms in the room heating radiato rs, whereas in and in spring and autumn, besides hot water at the faucet, heat may be wanted intermittently or occasionally in the radiators. I

Heretofore, various relatively simple and economical apparatus and control means therefor have been proposed for providing hot water for faucets or domestic purposes in conjunction with a radiator heating system where the system has been a steam system or a vacuum vapor system. However, where hot Water has been used as the heating medium, the first cost of suitable control devices and the installation has rendered such systems prohibitively expensive for providing heat both for the radiators and for faucet hot water purposes.

With the increasing popularity of hot water heat, there has been an increasing demand for apparatus and controls therefor for furnishing hot faucet water and which would not be prohibitive in cost. It is becoming more and more general practice, following the advent of automatic fuel fed boilers such as oil, gas, and stokercontrolled to provide hot water for faucet purposes at all times, winter and summer, at asubstantially constant temperature, andautomatically supply hot water to the room heating radiators only when necessary to maintain the rooms at a predetermined temperature.

Another object is to provide such a system in Which the temperature of the faucet water may be automatically thermostatically controlled in an improved manner.

Another object is to provide such a system in which the supply of hot Water to the radiators may be controlled in an improved manner responsive to temperature changes of the rooms to be heated.

Another object is to provide a hot water heating system in which the fuel supplying apparatus for a water heating boiler may be controlled automatically in a manner to maintain a supply of hot water in the boiler at all times, sufficient to heat a supply of faucet water and to maintain the same at a desired temperature and which supply of hot boiler water may automatically be admitted to the room heating radiators and circulated therein upon a thermostatic demand for higher temperature in the rooms to be heated.

Another object is to provide in connection with a Water boiler and heat supplying apparatus therefor and indirect heating means for heating a supply of faucet water, improved means for controlling the supply of fuel to the boiler.

Another object is to provide a hot water heating system automatically controlled to provide hot water for faucet purposes at all, times at a substantially constant temperature, and automatically supply hot water to the room heating radiator when necessary to maintain the room at a predetermined temperature, which is uninfiuenced by variations in the head of water maintained in the system.

Another object is to provide in connection with an automatically controlled hot water heating system adapted to provide hot water for faucet purposes and for room heating radiators, a means of maintaining the rooms at a predetermined temperature which will maintain a supply of hot water to the radiators irrespective of breakage or derangement of the normal operation of the system.

Other objects of my invention will be apparent to those skilled in the art to which my invention appertains.

' My invention is fully disclosed in the following description taken in connection with the accompanying drawings in which, 5

Fig. 1 is a view illustrating a form of my invention applied to the boiler of a heating system ofartype having a single circulating riser and return pipe and having an electrically actuated and controlled fuel'supply apparatus;

Fig. 2 is a diagram illustrating one form of an. electric control circuit which I may employ in connection with the boiler and fuel supplying apparatus of Fig. 1; p

Fig. 3 is a fragmentary view similarto a part of Fig. 1 but illustrating my invention applied to a boiler system of the type having two circulating risers and return pipes; I

Fig. 4 is an elevational sectional view of a thermostatically operated valve device which I may employ having hydraulic pressure balanced features;

Fig. 5 is a horizontal sectional view taken from the plane 5-5 of Fig. 4;

Fig. 6 is a, fragmentary view to a smaller scale of a part of Fig. 4 taken from the 'plane 44 of Fig. 4;

Fig. 7 is a view similar to Fig. 4 showing a modi fied form of thermostatically operated valve device which I may employ; and

Fig. 8 is a horizontal sectional view taken from plane 8- -8 of Fig. 7.

Referring to the drawings, I have shown at a boiler and at 2,' generally, a part of an automatic fuel supplying apparatus for heating the boiler.

The part 2 is shown generally in the form of a blower for supplying air for combustion purposes within the boiler and the other operative parts of the fuel supplying apparatus are not shown, being concealed within the base of the boiler. The part 2 therefore, may represent. a fuel supplying apparatus of any type suitable to automatically supply fuel to the boiler such for example, as an oil burner, gas burner, coal stoker, coal blower, etc., and inasmuch as all such apparatus is well known in this art, it is believed unnecessary to describe the same in detail.

The control of such automatic firing apparatus is commonly effected by an electriccircuit leading thereto and which in Fig. 1, is illustrated by the circuit wires 3 and 4. In other words, electric current flowing over the wires 3 and 4 to the apparatus -2 will cause the same to supply fuel to the boiler and heat the same in any of the several -well known types of apparatus and modes of operation thereof.

However, I contemplate that the control of the boiler firing apparatus may be eifecte drby other means than an electric circuit such as. controlling a gravity operated oil burner or a burner controlled by throttling of the fuel supply whereto the boiler by a return pipe 6 a well known manner.

Immediately above the boiler and in the line of the riser 5, I -pro'vide a thermostatically op"- erat'ed valve-device shown generally at 1, the. construction and operation of which presently be described. j v

Leading from the riser 5, is a conduit 8 communicating with an indirect water heater 3 from .which a returnconduit Ill leads back to the-boiler. The indirect water heater 3 may be of any suitable or known construction. T

Que such known indirect water heater comprises a shell through which a coil l2 extends communicating with the conduits 8 and In. Hot water from the boiler therefore may circulate through the coil l2. Water in the shell surrounding the coil |2 will therefore be, heated and by means of conduits I3 and I4 connected to a hot water supply tank may heat the water in the tank, the water circulating through the conduits VI 2 and I4 andshell II and storing up hot water in the supply tank in a well known manner.

I contemplate that various types of thermo- 1 static valve devices other than those hereinafter described may be employed in connectionwith this system, one such valve device being'described and illustrated ?(Figs. 6 and '1) in a copending application of William J. McGoldrick, Serial No. 616,344, filed June 9, 1932, for Theromstatic valves. 7

The thermostatic valve device 1 is shown separately in Figs. 4 and 5. An upper housing l6 and a lower housing I1 generally of cup shape having flanges 8 and I9 attheir open ends, are rigidly bolted together by bolts 20 projected through perforations in the flanges; the housings being recessed to provide circular shoulders 2| and 22 in housings l6 and I1 respectively. Partitions 23 and 24 are clamped between the flanges and are sealed therewith by a plurality of sealing rings 25 disposed intermediate the partitions and also seating upon the shoulders 2| and 22.

A valve seat constituting a portion of the peripheral edge of a large perforation 29 in the partition 24 has a coooperating valve 21 whereby the flow through the perforation or valve port 26 may be controlled.

The lower housing |1 communicates with the riser 5, an interiorly screw-threaded boss 28 being provided in the bottom wall of the housing l1 to receive the threaded end of the riser 5. Hot water in the riser 5 may therefore flow into the housing I1, and whenthe valve 21 is in the open position, may ,fiow through the port 26 upwardly through the housing l6 and out through an interiorly threaded boss I29 which communicates with a continuation 30 of the riser 5.

Substantially at the center of the circular valve 21, it is axially'threaded and a stud 3| is threaded thereinto, having a circular flange 32 adjacent rigidly secured to the stud 3| preferably by flang ing over portions of the stud above the'flange 32 to form a tongue and 'grooveconnection therebetween. The pressure bellows 34 comprises besides the head 33 an axially opposite head'35, the two heads being connected by a metal corrugated bellows wall 36.; The head 35 is rigidly secured to' a flanged threaded stud 31 in a manner previously described. The head joints are preferably soldered as indicated at 38 to ensure thatthe studs 3| and 31 will be in fluid tight relation with the pressure bellows 34.

The bellows 34 is rigidly secured to a bracket '39 integral with partition 23 through'a nut 40 which threadedly engages an end of stud 31 projected through an aperture provided in the bracket; Sealing washers 40a4||a are preferably provided to ensure-that the stud 31 will be inair tight relation with bracket 33. The stud 31 is provided with a longitudinal recess 4| adapted to communicate with 9. lat- 4 erally extending aperture 42 provided in bracket 33 and within which an end of a tube 43 is sealingly secured. The opposite end of the tube '43 is sealingly secured within an aperture provided therefor in the base portion of partition 23 whereby it will be in communication with the atmosphere and thus maintain the interior of bellows heater 9.

34 at atmospheric pressure at all times.

A thermostatic bellows generally indicated at 44 comprises a centrally apertured base 45 connected to the underside of valve 2! by a corrugated metal bellows wall 46. The underside of valve 27! is preferably annularly recessed to provide a face to which the bellows wall 46 is sealingly secured coaxial with valve 21. A threaded stud 47 is rigidly secured to the base 45 of the bellows preferably by fianging over portions of the stud extending beyond the circular flange 48 thereon to form a tongue which engages the peripheral edges of the base aperture. A sealing washer 38 is preferably provided to ensure that the bellows 44 will be in fluid tight relation with stud 41.

The stud 41 is disposed within an aperture provided therefor in a downwardly extending bracket 49 integral with partition 24 and is locked. therewith by a nut which threadedly engages the stud.

The stud 41 is provided with a longitudinalaperture indicated at 52 terminatingin an enlarged aperture adapted to engage a plug 53 whereby the bellows 44 may be supplied with a volatile fluid which can be sealed therein by; the plug 53.

A spring 54 is disposed within the thermostatic bellows 44 prior to assembly and at the lower end seats upon the base 45 and the upper end abuts the under face of valve 21. A centrally disposed generally circular boss 55 is preferably provided on the underside of valve 21 to ensure that the spring 54 wi1l be maintained in coaxial alignment the water in the boiler only to a maximum temerature of say 160 in a manner to be more fully described. Thermostatic bellows 44 is constructed'and adjusted so that up to a temperature 160 the valve 21 will be maintained on its seat to close the port 29 therethrough; and the hot water therefore will circulate only through the indirect If however, the heat demands of the system require that heat be supplied through the riser 5 to heat radiators, the automatic control of the firing apparatus will heat the water inthe boiler and therefore in the casing IT to a temperature above 160, and thereuponthe bellows device 44 will expand axially and open the valves 27- 'and the hot water from the boiler will at once begin to circulate, upwardly through the housing portion l6 and out through the riser 3B and thence to the radiators to supply heat thereto.

The bellows device 34 is uninfluenced by temperature, its interior being at all'times at atmospheric pressure and its function is to balancethe efiect of hydraulic heads upon the bellows device 44. Since the riser 30 may lead to radiators of considerable variation in height above the boiler even in private residences, hydraulic pressure in the housing l1 and therefore on the bellows 44 may be considerable and will tend to counteract the expansion of the bellows thermostatically.

The bellows 34, however, is subjectedto the same hydraulic pressure and any tendency to collapse is counter balanced by the tendency of the belagainst atmospheric pressure.

lows 44 to collapse, the bellows 34 exerting an upward thrust on the base 33 and the bellows 34 exerting a downward thrust on the valve 21 and' both the base and the valve being rigidly secured together. 1

' The spring 54 together with the expansion of the volatile filling of bellows '34 exert sufiicient pressure axially and upwardly at a temperature of substantially,160 to lift the valve 21 from the seat and permit the circulation of hot water through the ports. Howeven it is necessary to ensure that if the volatile filling within the bellows should escape for any reason and thereby lessen the pressure within the bellows, that the valve 21 will be heated water to the radiators. Otherwise, the valve would not open regardless of the temperature of the water within the housing I? and irrespective of the temperature of the rooms. The spring 54 acts as a positive means for forcing the valve 2'! to an open position if the volatile filling should escape fro-m the bellows 44, thus providing a safety feature preventing undue lowering of the temperature in the room and consequent danger to health and equipment. The pressure within bellows 44 if leakage should occur, will obviously eventually become equal to the hydraulie pressure exteriorly thereof in the housing H which will be exerting an upward thrust on valve 2'! in addition to the spring.

If the pressure bellows 34 should leak it would mean that the bellows would fully or partially fill with water which would replace all or a portion of the air within the bellows and would be subjected only to atmospheric pressure. Therefore as the valve 21 was raised upwardly it would force water from the bellows through the tube 43 It will thus be seen that the construction of the device is such that irrespective of a leak in either the thermostatic bellows or the pressure bellows that the valve will be forced open at substantially the I desired temperature.

v The control of the boiler to maintain temperature of the water therein at or below amaximum temperature of say 160 when water for the indirect heater of the faucet water supply tank only is needed, and to raise the temperature of the water in the boiler to effect opening of the thermostatic valve and to circulate same through the heating radiators when a need for heat arises in the rooms to be heated, will now be described.

Referringto Fig. 2 I have shown generally at 80 a room thermostat comprising a stationary contact 8|, and a movable contact 82 the latter being carried by the movable arin 83 which is connected to a thermostatic element 84. Upon changes of surrounding room temperature, the thermostatic element 84 will effect a movement of the contact 82 to engage the contact 8| or to disengage the same in a well known manner.

Generally at 85 I have illustrated a thermostat of the so-called immersion type that is to say, a thermostatic device having a generally tubular element 86 adapted to be inserted or water on the element 83 falls to a predetermined value and vice versa.

At 88 is indicated another thermostatic device of the immersion type which may be identical with or similar to the device 85.

Within a housing 87, an

The thermostat 88 is situated in a room to which heat is to be supplied. The thermostat 85 has its immersion element 86, as shown generally in Figs. 3 and 4- disposed in the housing portion II adjacent the thermostatic bellows 48 and the thermostatic device 88 has its immersion element 89 disposed in the same housing portion, and thus both thermostats are subjected to the temperature of water in the said housing portion.

The thermostat 85 is adjusted so that it will operate to open its contacts when the water temperature on its element 86 reaches 160. The thermostatic device 88 however, is adjusted so that it will open its contacts at some suitable temperature above 160 for example 170, a- 10 degree differential being preferred as thus indicated.

In the operation of the system therefore, if as in the summertime the rooms to be heated do not demand heat, the thermostat 88 will open its contacts toshut down the fuel supplying apparatus 2 but the contacts of the thermostat 85 will remain closed and thus actuate the apparatus 2 to keep the water heated up to but not beyond 160 whereby it will supply heat to the indirect faucet water heater 9. If however, the water rises in temperature above 160, the thermostatic device 85 will open its contacts, and the contacts of the thermostat 88 being open, the apparatus ,2 will be completely shut down. If the temperature of the boiler water falls below 160 or a predetermined difierential amount below 160, the contacts of the'device 85 will close and start up the apparatus 2 to restore the boiler water temperature.

Thus the device 85 will maintain the boiler water at a suitable temperature to heat the faucet water tank. If however, the room temperature should fail it will close the contacts of the device 88 and this, will actuate the apparatus 2 irrespective of the thermostat 85 and even if the latter opens its contacts, fuel will continue to besupplied to increase the temperature of the boiler water beyond the 160 specified. The water will thus continue to increase in temperature until it reaches say the temperature of 170 according to which the bellows thermostat 44 is adjusted whereupon the thermostat 44 will open the valve 21 and the hot water will begin to circulate through the radiators to raise the temperature of the rooms. If the rooms are slow to heat up and the boiler temperature continues to increase or overrun the desired temperature at which, after the rooms once become.warm, it may be kept warm, such temperature will operate the thermoboiler'water hot, the thermostat 85 keeping it up 4 1 to'but not beyond 160 and the thermostat 88 raising it above 1607 whenever" this isnecessary to maintain; room temperature; and the device Figs. 3 and 4 will shut off the circulationof hot water to the radiators and limit the circulation to-the indirect heater by closure of the valve 21 when the room thermostat does not demand heat.

The thermostatic switch devices 85 and 88 may as stated, be of any suitable construction, comprising an immersion element 86 or 89 which may be inserted into the boiler water and coniprising switch contacts which will be opened when the temperature reaches predetermined adjusted values. One such suitable thermostatic switch device is illustrated in the pending application of C. W. Bondurant, filed February 12,

. compensate for the pressure of hydraulic head in the riser may be employed.

Referring again to Figs. 4 and 5 I have indicated at 95 the connection from the'housing I! to the conduit 8 leading to the indirect water heater; and I have indicated generally therein an aperture adapted to have an air relief valve 96 inserted therein whereby any accumulation of air in the valve apparatus may be discharged to the atmosphere.

In'Fig. 31 have indicated. generally the-preferred arrangement when there are two water supplying risers. .The riser 5, thermostatic valve device I, and riser 38 have been reproduced as in Fig. 1. The second riser I88-I82 has interposed in the line thereof a second thermostatic valve device I81 which may be identical with or similar to the device I. A pipe I88 connects the upper housing portion I89 of the device I81 with relief valve 98 of the device I whereby upon operating the valve 96, both thermostatic devices maybe drained of accumulated air in a well known manner.

The device I8! is not provided with any thermostatic switch devices such as 85 and 88 as is the device 1., The lower housing portions I'I-I'I of both the devices I and I8! are connected by conduits H8 and III to a single conduit II2 for supplying heating water to the indirect heater 9.

In this form, the control of the heat supplying device 2, is responsive to temperature conditions in the device 'I.' The electric circuit in connectionwith this form may be the same as that for the form of Fig. 1. A response of the boiler to room temperature may be controlled by a room thermostat 88; each riser may have its flow cut ofi independently by its respective device I or I81; and the minimum and maximum boiler temperatures may be controlled by thermostats 85 and 88 in association with device I in the riser 5. I I

In the modified form of my invention of Fig. 7,

I show a form of thermostatic valve device which.

is not compensated for fluid pressure of the hydraulic head of water in the risers, such a simplifiedconstruction,belng adapted fora specific installation wherein thehydr ulic head to which it is subjected is known and in correspondence with which it may initially be constructed and upper portion I and lower portion I2I clamped together by bolts I22 upon a partition I23 sealed to the housing portion by washers I.24-I24 is provided.

A valve I25 adapted to close the valve port I26 is screw-threaded as at I2'I upon a stem I28 and thus may axially be adjusted along the stem and locked in adjusted position by a nut I29. The stem I28 has a duct I30 therethrough' by which thermostatic fluid may be conducted initially to the interior of a collapsible bellows I3I, the stem I28 being rigidly and sealedly connected as at I32 to an upper head I33 of the bellows. The lower end of the bellows is sealedly connected as at I34 to a circular head I35 supported by brackets I38I38 secured as by rivets I3'I to the-parti tion I23.

A spring I39 within the bellows I3I abuts upon the opposite head thereof and opposes the collapsing effect of hydraulic pressure on the bellows. The stem I28 is guided for vertical coaxial movement in a bore I40 provided in the head I4 I supported by generally radial brackets I42 connected to or formed integrally with the partition I23.

In the operation of the form of my invention in Fig. 5, the valve I25 will be opened to permit the flow of fluid from the riser 5 to the riser portion 8 through the valve port I26 when temperature of water in the housing portion I2I rises to a predetermined value responsive to which the ther-' mostatic bellows is adjusted. This value can be adjusted by adjusting the axial position of the valve I25 along the stem I28 as will be understood, as well as by a predetermination of the quantity of and thermal characteristics of the expansible fluid injected initially into the bellows I3I through the duct I30 and sealed therein by the plug I45.

In connection with either of the forms of the thermostatically operated valve device of Figs. 4 and 5, or Fig. 6, it will be observed that the boiler water continuously circulates through the indirect heater so that the water in the valve device is maintained at the temperature of the water in the boiler so thatthe thermostat of the thermostatically operated device I for example, is always subjected to the boiler water temperature even when the valve is closed and flow through the riser is shut off. Thus the conduit system to the indirect water heater performs an additional function to that of. merely supplying heat to the heater, namely, the function of communicating to the thermostat in the riser, thetemperature of the water in the boiler.

In the absence of such a local circulating system, it will be understood that the water in the boiler might attain a temperature many degrees different from that in the riser when the riser valve is closed.

Water for the indirect heater may be conveyed out of the housing portion I2I by conduit 8 and the immersion elements 89 and 86 of thermostatic devices and 88 may be projected into the housing portion I2I as more completely described hereinbefore in connection with the other form.

The thermostatic'switch device 85 is preferably mounted substantially at or above the top plane of thermostatic bellows 44 and above the limit control thermostatic switch 88.' The bellows 44 is calibrated to open the valve 21 when surrounded by water at a predetermined temperature say The thermostatic switch device 85 operates to shut down the fuel supply apparatus when the water temperature goes above a definite point as 160 and is only operative when the room thermostat is not calling for heat.

If air were trapped beneath the valve 21 and above bellows 44 a relatively higher temperaturewould be required to expand the bellows sufficiently to operate valve 21, say due to the fact that the bellows is not surrounded by water.

'If the thermostatic switch device were mounted at the bottom plane of the bellows it would not permit the water to attain a temperature of above 160? and consequently when the room thermostat demanded heat and rendered device 85-inoperative, the water would have to heat to 165 before the valve 21 would open.- When the device 85 is mounted as indicated it will not shut down the fuel supply apparatus until the immersion element has attained a temperature of 160 and since it is mounted at substantially the top plane of or above the bellows 44, the bellows will be subjected to 160 and consequently will operate immediately to open. valve 21 upon a demand for heat from the room thermostat and will thus vent any trapped air. The air may then be vented to the atmosphere by any automatic air relief valve.

The waterstat if installed in a horizontal position is preferably supplied with an automatic air relief valve of the float type since it is essential to the proper functioning of the apparatus that a minimum level of water. be maintained in the waterstat.

The waterstat may be utilized through proper adjustment to minimize the time interval or lag encountered between the time at which the room thermostat signals for heat at a predetermined minimum temperature and the time at which this temperature is attained. For instance, the room thermostat may be set to demand heat at 70 but due to the time necessary to effect this result, the temperature will go and remain below 70 for a period, thus giving rise to. a condition known as cold 70. (The thermostat set at 70 yet the room is colder than the set temperature.)

This condition is aggravated in mild weather when the boiler has not been called upon to heat water for the radiators but due to a drop in temperature such heat is required. Obviously,

. a relatively large amount of time will be required to heat the body of water in the boiler to the desired temperature and replace the water of low temperature in the heating system.

The waterstat affords a means of maintaining heated water in the radiator system at substantially the desired temperature irrespective of the room thermostat due to the throttling action of the valve. Thus the bellows being adjusted to open valve 21 when a. predetermined temperature in the housing is attained, will permit water at substantially this temperature to flow to the radiator system. This water will be replaced by water a few degrees colder causing the bellows to contract and close the valve. This continuous throttling action ensures that a supply of heated water will be maintained in the radiator system at a temperature dependent on the temperature within the waterstat. Thus,

the radiator system is always maintained at s bstantially the desired temperature and the ti e interval required, to bring the room to this desired temperature is reduced to a minimum.

Although I have described embodiments of my invention, I contemplate that numerous and extensive departures may be made therefrom without departing from the spirit and scope of my invention and the appended claims.

Having thus-described my invention, what. I

claim is:-'

- ture thermostat being rendered inoperative when ducting circuits comprising a room heating circuit and a hot water supply circuit, a throttling valve for one circuit operatively responsive to the temperature of that circuit, and compensating means whereby the valve will operate at substantially the same temperature irrespective of fluid head.

2. In a fluid heating system, a boiler, boiler fuel supply apparatus, two fluid conducting circuits comprising a room heating circuit and a hot water supply circuit, a throttling valve forone circuit operatively responsive to the temperature at the common source, anda thermostat responsive to fluid temperature controlling the fuel supply apparatus.

3. In a fluid heating system, a boiler, boiler fuel supply apparatus, two fluid conducting circuits comprising a room heating circuit and a hot water supply circuit, a throttling valve for one circuit operatively responsive to the boiler temperature, a thermostat controlling the fuel supply apparatus responsive to fluid temperature, a second thermostat controlling the 'fuelsupply apparatus responsive to room temperature, the fluid temperature thermostat being rendered inoperative when the room temperature falls below a predetermined value. I a

peraturey at the common source, thermostatic means controlling the fuel supply apparatus responsive to room temperature, the fluid temperathe room temperature is below apredetermined value, and a third thermostat limiting the fluid temperature and'adapted" to render the room thermostat inoperative." j -5.. In a heatingsystem, incombination with a boiler and a-main circulating conduit for -'sup-" plying heat at a point-of 11se',avalve controlling flow through the conduit,- a thermostat for'operating the valve disposedexternally of the boiler and 'responsivetoifluid "temperature and a lo'calfj circulating conduit for conducting boiler fluid to the thermostattomaintain-it substantially at the--temperature of the-water in the "boiler when the valve is closed,- and' said local circulating" conduit supplying heat to: afaucet water heater. l -6. In a heating system, in conibinationwith a boiler and a main circulating conduit for supplying heatat a point 'of'use, a thermostatic valve I device in'theconduit line of flow comprising a valve controlling the'fiow-and a fluid temperature responsive -thermostat adapted to operate the -valve,' alocal circuit conduit-communicating 1 with -the" line=of'flow at a pointadjacent tothe'f thermostat, and adapted to communicate tem perat-ure'oi fluid in the boiler to the'thermostat when the valve is closed, "an-electrically -con'- trolled heat-supplying apparatus for the boiler, 'an'electric 'circuit'therefor, and athermostatic switch controlling the 'circuit and responsive to temperature of fluid'at the said valvethermostat perature of the water; below the valve-opening H temperature of the valve thermostat.

1. In a fluid heating system, two fluid coning a valve controlling. the flow and a fluid temperature responsive thermostat adapted to operate the valve, a local circuit conduit communicating with the line of flow ata point adcontrolled heat-supplying apparatus for the boiler, an electric circuit therefor, a thermostatic switch controlling the circuit and responsive to temperature of fluid at the said valve thermostat when said valve is closed to maintain the temperature of the water below the valve-opening temperature of the valve thermostat, and the thermostatic switch controlling the circuit and responsive to temperature below a predetermined value at the point of use to effect an increase of fluid temperature at the valve thermostat to cause the valve to open irrespective of the control of the first mentioned thermostatic switch.

8. In a heating system, comprising a water boiler and amain circulating conduit for supplying heat at a point of use, a thermostatic valve device in the conduit line of flow comprising a valve controlling the flow and a water temperature responsive thermostat'adapted to operate the valve, a local circulating conduit communicating with the line of flow at a point adjacent the-thermostat and adapted to communicate temperature of water in the boiler to the thermostat an electrically controlled heat supplying apparatus for the boiler, an electric circuit therefor and a thermostatic switch controlling the circuit and'responsive to temperature below a predetermined value at the point of use .to effect an increase of water temperature at the valve thermostat to cause it to open the valve.

9. In aheatingsystem, in combination with a water boiler and a main circulating conduit for supplying heat at a point of use, a thermoadapted tc'operate' the valve, a local circuit conduit communicating with the line of flow at-a" point adjacent'to the thermostat, and adapted to'communicate' temperature of water in the boiler to the thermostat when the valve is 'closed,"

an electrically controlled heat supplying appa' ratusior the boiler an electric circuit therefor)" maintain the temperature .of the water below the .vaIVe-Qpening temperature of the valve at the ,valve. thermostat to cause, it to open .the

thermostat, a thermostatic switch controllingthe circuit and responsive to"temperature'belowa predetermined value at the point of use toeffect an increase of boiler water temperature;

valve irrespective ofrthe control ,by thegflrst said. thermostat, .and a-,thermostatic -s witch controlling. the circuit responsive to 1 9?! l filje ;at the valve thermostat to maintain the wa-tefltemperature below a predetermined maximum .irrespec- "tive of the control by the v second said thermostat at the point of use.

10 The method of controlling the circulation i of fluid in a fluid heating system comprisinga boiler and an electrically-actuated boiler heat- '1.- In a heating system,'=in combination with-a ing apparatusfiherefor which includesshutting off the circulation by 'athe i'mostatically perated valve at the boiler respon'siv'e to flui'dftemperature, maintaining a local; circulation"6f tbailer. i

fluid and heating the valve thermostat thereby, maintaining said local circulation at a predetermined minimum temperatureby a thermostatic electric switch responsive to said fluid temperature and controlling the boiler heating apparatus, controlling the boiler heating apparatus by a room temperature responsive thermostatic switch to increase the temperature at the valve thermostat to open the valve when the room temperature falls to a predetermined value independently of the control by the first thermostat and controlling the boiler heating apparatus by a third thermostat responsive to boiler water temperature to prevent a rise thereof above a predetermined value independently of the room thermostatic control.

11. A heating system substantially as described in claim 4, characterized by the throttling value comprising a contractible and expansible bellows subjected to head of fluid pressure in the room circuit and in whichmeans is provided to compensate for the bellows collapsing tendency of the fluid pressure. v 12. A heating system substantially as described in claim,4, characterized by the throttling value comprising a bellows of the contractible and expansible type, a second bellows to compensate for the bellows collapsingtendency of the fluid head, and wherein means are provided to open the valve at substantially the desired temperature irrespective of derangement of either bellows.

13. In a heating system, a boiler, a fluid circulating conduit connected to the boiler to supply heat at a point of use, a valve in the conduit disposed externally of the boiler, a thermostat of the expansible and contractible sealed chamber type containing thermally expansible fluid chamber type containing thermally expansible fluid adapted to open and close the valve .at ipre determined fluid temperatures, a local circulating conduit for conducting fluid of boiler temperatures to the thermostat, and meansconstantly acting tending to open the valve and operable upon loss of seal of the thermostatic chamber. 1

15. A heating system as described in claim 13 and in which the thermostat is of the bellows type and the means to openthe valve is a spring. 16. A heatingsystem as described in claim 13 and in which the thermostat is of the bellows type and a spring is disposed within the bellows reactingupon the valve to open it uponithe occurrence of a, loss of seal of the bellows.

17. A heating system as described in claim 13 and in which the chamber type thermostat is subjected to the pressure of liquid head in the circuit, and a second expansible and contractible chamber, subjected to the pressure of liquid head in the circuit, opposes the tendency. of the firstnamed chamber to collapse under the head of pressure.

jected to the pressure of liquid head in the circuit, and a second exp-ansible and contractible chamber communicating interiorly with the atmosphere'is subjected to the pressure of liquid in the circuit and opposes the tendencyof the first-named chamber to collapse under the pressure of the liquid head.

19. A heating system as described in claim 13 and in which the chamber type thermostat is subjected to the pressure of liquid head in the circuit and a second expansible and contractible chamber, subjected to the pressure of liquid head in the circuit, opposes the tendency of the firstnamed chamber to collapse under the head of pressure and the means to open the valve upon loss of seal is a spring acting upon the valve in the same direction as the thermostatic chamber.

20. In a thermostatic valve device, a housing adapted to be connected in the line of flow of a conduit, a valve in the housing controlling flow therethrough, a thermostatic bellows in the housing containing thermally expansible fluid and having a movable wall connected to the valve to move it to open position uponthermal expansion of the bellows, a second bellows having a movable wall connected, to the first-named movable wall and communicating interiorly with the atmosphere externally of the housing, both said bellows being subjected to the pressure of fluid head in the conduit, and means exerting resilient force in the valve opening direction only and constantly acting-in that direction tending to move the valve to open position and operable to open it upon failure of seal of the thermostatic bellows.

21. A thermostatic valve device as described in claim 20 and in which means is provided to simultaneously adjust the force of the constantly acting means and the valve opening force exerted by the thermostatic bellows. w

'22. In a heating system, a boiler, a fluid circulating conduit connected to the boiler tic-supply heat at a point of use, a valve in the cggnduit disposed externally of the boiler, .a ther ostat adapted to open and close the valve at predetermined fluid temperatures, a local circu lating conduit for, conducting fluid..- of; boiler temperature to the thermostat, and 1 means to open the valve upon failure of .the.ther mo stat.

23. .-In a' heating system, a boiler, awfluid' cir-- culating conduit connected ,to theboiler ;to sup- 1 ply heatat a point of use',.a valve in the conduit disposed externally of the boiler, a thermostat adapted to open and close the valve at predetermined fluid temperatures, a local circulating con- -duit for conducting fluid of boiler temperature to the thermostat, means to open the valve upon ;iailure of thethermostat, and means constantly acting and tending to open the valve and operable uponfailureof the-thermostat. r

24.-In a combined hot Water supply and heating system, awater boiler, means for heating said-boiler, a domestic water supply tank, a heat exchange unitin circuit'with said boilenforvindirectlyheating thewa'ter in said supply tank,

thermostatic means in said circuit for.:co-ntrolli'ng the temperature of the water flowing through said exchange unit, a house heating system also in circuit with said boiler, thermostatic means in said .house for increasing the heat supplied to said boiler when the room temperature falls below normal, and thermostatic means responsive to the boiler temperature for controlling the flow of hot water in said house heating circuit.

25. In a combined hot water supply and heating system, a water boiler, means for heating said boiler, a domestic water supply tank, a heatexchange unit in circuit with said boiler for indirectly heating the water in said supply tank, thermostatic means in said circuit for controlling the heat supplied to said boiler for regulating the temperature of the water flowing through said exchange unit, a house heating system also in circuit with said boiler, and thermostatic means responsive to the boiler temperature for controlling the flow of hot water in said house heating circuit.

26. In a combined hot Water supply and room heating system, a water boiler, means for heating said boiler, a heat exchanger for a hot water supply system in circuit with said boiler, means responsive to the temperature of the water in said heat exchanger circuit for controlling the supply-of heat to said boiler, a room heating system in a separate circuit with said boiler, means responsive to the room temperature for independently controlling the supply of heat to said boiler, and a thermostatically controlled valve in said room heating circuit responsive to the boiler temperature for connecting said room heating circuit to saidiboiler when said boiler temperature exceeds a predetermined point.

27. In an automatically controlled room heating and domestic hot water supply system, a water boiler, means for heating said boiler, a room heating system in circuit with said boiler, a heat exchanger for a hot water supply system also in circuit with said boiler, thermostatic means responsive to the temperaturein said heat exchanger circuit for controlling the supply of heat to said boiler, a room thermostat adapted to increase said heat supply when the room temperature falls below normal, a thermostatically controlled valve in said heating system circuit adapted to open and permit hot water to circulate in said room heating system when the temperature in said boiler exceeds a predetermined point.

28. In a combined hot water supply and room heating system, a water boiler, means for heating said boiler, a heat exchanger for a hot water supply system in circuit with said boiler, means responsive to the temperature of the water in said heat exchanger circuit for controlling the supply of heat to said boiler, a room heating sys-- tem in a separate circuit with said boiler, and

4 adjustable valve means responsive to the boiler tus for heating fluid in the boiler above normal temperature, a thermostat of the immersion type having an immersion element projected into fluid in the housing and controlling the apparatus to control the supply of fuel to the boiler responsive to changes of temperature of the fluid in the housing to maintain the fluid at a temperature above normal but below the valve opening temperature of the thermostat.

30. In a thermostatic valve device, ahousing adapted to be connected in the line of flow of a conduit, a valve in the housing controlling flow therethrough, a thermostatic bellows in the housing containing thermally expansible fluid and having a movable wall connected to the valve to move it to open position upon thermal expansion of the bellows, and means exerting resilient force on the valve in the openingv direc tion and constantly acting in that direction to move the valve to open position and operable to open it upon failure of seal of the thermostatic bellows, and means to simultaneously and, commensurably adjust the force of the constantly acting means and the valve opening force exerted by the thermostatic bellows.

31.-A fluid heating system controlling mechanism adapted for inclusion in a heating system comprising an electrically controlled fluid'heater, a main heating fluid circulating conduit leading to room heating radiators of the system, and an indirectly heated water circulating conduit for providing a source of hot water supply, said mechanism comprising a valve device disposed in the line of flow of the main conduit, thermostatic means adapted to control fluid flow through the valve device and main conduit responsive to the temperature of fluid passing through the valve, and thermostatic switch means associated with the valve device and controlling the fluid heater to maintain a predetermined minimum temperature in the indirectly heated conduit and to render said heater inoperative at a predetermined maximum temperature of fluid passing from the heater to the valve device.

32. A fluid heating controlling mechanism comprising an electrically controlled fluid heater, a main heating fluid circulating conduit leading to room heating radiators of the system, and an indirectly heated water circulating conduit providing a source of hot water supply, said mechanism comprising a valve device disposed in the EDWARD LEVY MAYO. 

